1. Field of the Disclosure
The present disclosure relates to a liquid crystal display device, and more particularly, to a liquid crystal display device having a camera therein.
2. Discussion of the Related Art
Recently, various flat panel display devices have been developed. Examples of the display devices, which have been actively studied, include a liquid crystal display device, a plasma display panel, a field emission display device, and a light emitting display device.
Of the flat panel display devices, the liquid crystal display (LCD) device is a device that displays images using optical anisotropy of a liquid crystal, and is widely used owing to its advantages of thin type, small size, low power consumption, and high picture quality.
FIG. 1 is a plane view illustrating a liquid crystal display device according to the related art, and illustrates that an upper substrate and a lower substrate are bonded to each other by a seal. FIG. 2 is an exemplary view illustrating a section in the periphery of a through hole of a liquid crystal panel according to the related art.
According to the liquid crystal display device, the upper substrate and the lower substrate are bonded to each other in a state that a liquid crystal is filled between the upper substrate and the lower substrate. A liquid crystal layer between the upper substrate and the lower substrate is sealed by seals 11e, 11m, 11n and 11p formed outside the liquid crystal panel.
The liquid crystal display device may be divided into a display area where various elements are formed to display images, and a non-display area formed outside the display area. In this case, the seals 11e, 11p, 11m and 11n may be divided into the first seal 11e formed between the first non-display area having a camera therein and the display area, and the second to fifth seals 11f, 11m, 11n, and 11p formed outside the liquid crystal display device at the non-display area of the liquid crystal display device in rectangular shapes, sealing the upper substrate and the lower substrate.
At the lower substrate of the liquid crystal display device, pixels are formed per area where a gate line crosses a data line. A liquid crystal injected into the pixel is driven by a voltage applied to a common electrode and a pixel electrode formed at the pixel, so as to vary transmittance of light.
The common electrode may be formed in the display area of the upper substrate or the lower substrate. In order to apply a common voltage to the common electrode, a common line connected with the common electrode is formed in the non-display area of the lower substrate or the upper substrate.
With the recent trend that intends to reduce an edge width of the liquid crystal display device, the common line is formed in the upper substrate to overlap the seals 11e, 11m, 11n and 11p as shown in FIG. 1, wherein the seals are attached onto the common line.
In case of the liquid crystal display device having a camera for video chatting, video conference, etc., as shown in FIG. 1, the first seal 11e formed between the first non-display area 12 and the display area 36 is extended to the first non-display area 12 to surround a through hole 14 formed in the first non-display area 12 to correspond to the camera.
In other words, in the liquid crystal display device according to the related art, light is refracted at an empty space between the lower substrate and the upper substrate where the through hole 14 is formed, whereby a diffraction pattern is generated in the image taken by the camera. In order to prevent such a diffraction pattern from being generated, a method for injecting a liquid crystal into the periphery of the through hole 14 has been used recently. To this end, the first seal 11e formed between the display area 36 and the first non-display area 12 is formed to surround the through hole 14.
Accordingly, no seal is formed between the periphery of the through hole 14 of the first non-display area 12 and the display area. For this reason, the liquid crystal injected into the display area is also injected into the periphery of the through hole 14.
An alignment layer is formed on a surface of the upper substrate and the lower substrate, which face each other, to increase an alignment power of the liquid crystal.
However, in the liquid crystal display device according to the related art, the alignment layer is formed in the display area 36 only of the upper substrate and the lower substrate, and is not formed in the non-display area 12 including the periphery of the through hole 14.
As described above, as the alignment layer is formed in the display area 36 only of the upper substrate and the lower substrate and is not formed in the non-display area 12 including the periphery of the through hole 14, problems occur as follows.
First of all, since the alignment power of the liquid crystal is not deteriorated in the periphery of the through hole 14, the liquid crystal may not be injected into or may not be uniformly injected into the periphery of the through hole 14.
Second, after thermal hardening for the seal for bonding the upper substrate to the lower substrate, the liquid crystals in the display area 36 may be shifted to the periphery of the through hole 14 which is not filled with the liquid crystal. In this case, liquid crystal alignment of the display area 36 may be distorted, whereby a defect may occur in the entire display area.
Third, as shown in (a) of FIG. 2, if rubbing is performed for an alignment material 13b, which is deposited on the display area of the upper substrate 13a, by using a roller 40, foreign materials scattered from the alignment material 13b by rubbing are scattered in the periphery of the through hole 14 located in the first non-display area 12 of the upper substrate 13a, whereby the foreign materials may be deposited on the through hole 14. In this case, noise may occur in the image taken in the liquid crystal display device.
Finally, the rubbing process for forming the alignment layer is performed on a mother substrate where a plurality of upper substrates or lower substrates are formed. In this case, a first display area of a first color filter substrate and a second display area of a second color filter substrate, where the alignment layer is formed, adjoin each other by interposing the first non-display area therebetween as shown in (b) of FIG. 2, wherein the first non-display area is provided with the through hole 14. Since the alignment material 13b constituting the alignment layer is not formed in the through hole 14 and the first non-display area 12 provided with the through hole 13, the surfaces of the alignment materials 13b formed in the two display areas are spaced apart from each other at a certain interval (for example, 12.12 mm). Also, the first non-display area 12 of the first color filter substrate arranged between the two display areas is recessed. Accordingly, if the roller 40 is shifted on the surface of the mother substrate to perform rubbing for the alignment material 13b, impact may be applied to the end A of the first display area of the second color filter substrate by the roller 40 which is moving after rubbing the first display area of the first color filter substrate. For this reason, vibration may occur in the entire of the mother substrate. This vibration may cause a defect of the alignment layer, whereby a defect of the liquid crystal display device may be caused.